Many materials in which a layer with high function is provided on a substrate are used in various kinds of products, for example, an LSI, a semi-conductor, a displaying device, a magnetic recording device, light to electricity conversion device, a Josephson device, a solar battery, and a light heat conversion device. Examples of the layer with high function include an electrode layer, a dielectric protective layer, a semi-conductor layer, a transparent electro-conductive layer, an electrochromic layer, a fluorescent layer, a superconduction layer, a dielectric layer, a solar battery layer, an anti-reflection layer, an anti-abrasion layer, an optical interference layer, a reflection layer, an anti-static layer, an electroconductive layer, an anti-stain layer, a hard coat layer, a subbing layer, a barrier layer, an electromagnetic radiation shielding layer, an infrared ray shielding layer, a UV absorption layer, a lubricant layer, a shape-memory layer, a magnetic recording layer, a light emission element layer, a layer applied to organisms, an anti-corrosion layer, a catalyst layer, a gas-sensor layer, and a layer for decoration. These layers with high function are formed according to a wet coating method such as a solution coating method or according to a dry coating method employing vacuum processing such as a spattering method, a vacuum evaporation method or an ion plating method.
The solution coating method is advantageous in high productivity, but is not necessarily suitable for formation of a layer with high function, since it is necessary to dissolve or disperse materials constituting the layer in a solvent to prepare a coating solution, and when the coating solution is coated on a substrate to form a layer, the solvent used remains in the resulting layer or it is difficult to obtain a layer with a uniform thickness. The solution coating method further has problem in that at the drying process after coating, the solvent evaporated from the coating solution pollutes environment.
On the other hand, the dry coating method employing vacuum processing can provide a layer with high precision and is preferable in forming a layer with high function. However, the dry coating method, when a substrate to be processed is of large size, requires a large-scale vacuum processing apparatus, which is too expensive and time-consuming consuming for evacuation, resulting in disadvantage of lowering of productivity. As a method for overcoming the demerits in that the solution coating method is difficult to provide a layer with high function or use of a vacuum processing apparatus results in lowering of productivity, a method is described in Japanese Patent O.P.I. Publication Nos. 11-133205, 2000-185362, 11-61406, 2000-147209, and 2000-121804, which comprises subjecting a reactive gas to discharge treatment at atmospheric pressure or approximately atmospheric pressure, exciting the reactive gas to a plasma state and forming a layer on a substrate (hereinafter referred to also as an atmospheric pressure plasma method). The atmospheric pressure plasma method disclosed in these publications generates discharge plasma-between two opposed electrodes by applying pulsed electric field with a frequency of from 0.5 to 100 kHz and with a strength of electric field of from 1 to 100 V/cm. However, although a layer with high function can be formed in only a small area according to the atmospheric pressure plasma method disclosed in the aforementioned publications, it is difficult to form a uniform layer over a large area. Further, it has been proved that the layer formed does not sufficiently satisfy performance to be required for a layer with high function. Accordingly, a means for solving these problems occurring in the layer formation as described above has been required.
The present invention has been made in view of the above. An object of the invention is to provide a method of uniformly forming a layer with high function over a large area with high productivity and with high production efficiency, a product comprising the layer, and an optical film comprising the layer, and to provide a dielectric coated electrode and a plasma discharge apparatus for carrying out the method and obtaining the product and the optical film.